> ## Documentation Index
> Fetch the complete documentation index at: https://old-docs.kie.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Flux-2 - Text to Image
> High-quality photorealistic image generation powered by Flux-2's advanced AI model
## Query Task Status
After submitting a task, use the unified query endpoint to check progress and retrieve results:
Learn how to query task status and retrieve generation results
For production use, we recommend using the `callBackUrl` parameter to receive automatic notifications when generation completes, rather than polling the status endpoint.
## Related Resources
Explore all available models
Check credits and account usage
## OpenAPI
````yaml market/flux2/flex-text-to-image.json post /api/v1/jobs/createTask
openapi: 3.0.0
info:
title: Flux-2 API
description: kie.ai Flux-2 API Documentation - Text to Image
version: 1.0.0
contact:
name: Technical Support
email: support@kie.ai
servers:
- url: https://api.kie.ai
description: API Server
security:
- BearerAuth: []
paths:
/api/v1/jobs/createTask:
post:
summary: Generate image using flux-2/flex-text-to-image
operationId: flux-2-flex-text-to-image
requestBody:
required: true
content:
application/json:
schema:
type: object
required:
- model
properties:
model:
type: string
enum:
- flux-2/flex-text-to-image
default: flux-2/flex-text-to-image
description: >-
Model name for the generation task. Required field.
- This endpoint must use the `flux-2/flex-text-to-image`
model
example: flux-2/flex-text-to-image
callBackUrl:
type: string
format: uri
description: >-
Callback URL to receive notifications when the generation
task is completed. Optional configuration, recommended for
production environments.
- After the task is generated, the system will POST task
status and results to this URL
- The callback content includes the generated resource URL
and task-related information
- Your callback endpoint needs to support receiving POST
requests with JSON payloads
- Alternatively, you can call the task details endpoint to
actively poll task status
- To ensure callback security, see [Webhook Verification
Guide](/common-api/webhook-verification) for signature
verification implementation
example: https://your-domain.com/api/callback
input:
type: object
description: Input parameters for the generation task
properties:
prompt:
description: >-
Generation prompt, length must be between 3-5000
characters. (Maximum length: 5000 characters)
type: string
maxLength: 5000
example: >-
A humanoid figure with a vintage television set for a
head, featuring a green-tinted screen displaying a
`Hello FLUX.2` writing in ASCII font. The figure is
wearing a yellow raincoat, and there are various wires
and components attached to the television. The
background is cloudy and indistinct, suggesting an
outdoor setting
aspect_ratio:
description: Aspect ratio of the generated image.
type: string
enum:
- '1:1'
- '4:3'
- '3:4'
- '16:9'
- '9:16'
- '3:2'
- '2:3'
default: '1:1'
example: '1:1'
resolution:
description: Output image resolution.
type: string
enum:
- 1K
- 2K
default: 1K
example: 1K
required:
- prompt
- aspect_ratio
- resolution
example:
model: flux-2/flex-text-to-image
callBackUrl: https://your-domain.com/api/callback
input:
prompt: >-
A humanoid figure with a vintage television set for a head,
featuring a green-tinted screen displaying a `Hello FLUX.2`
writing in ASCII font. The figure is wearing a yellow
raincoat, and there are various wires and components attached
to the television. The background is cloudy and indistinct,
suggesting an outdoor setting
aspect_ratio: '1:1'
resolution: 1K
responses:
'200':
description: Request successful
content:
application/json:
schema:
allOf:
- $ref: '#/components/schemas/ApiResponse'
- type: object
properties:
data:
type: object
properties:
taskId:
type: string
description: >-
Task ID, can be used to call the task details
endpoint to query task status
example: task_flux-2_1765175490366
example:
code: 200
msg: success
data:
taskId: task_flux-2_1765175490366
'500':
$ref: '#/components/responses/Error'
components:
schemas:
ApiResponse:
type: object
properties:
code:
type: integer
enum:
- 200
- 401
- 402
- 404
- 422
- 429
- 455
- 500
- 501
- 505
description: >-
Response status code
- **200**: Success - Request has been processed successfully
- **401**: Unauthorized - Authentication credentials are missing or
invalid
- **402**: Insufficient Credits - Account credits are insufficient
to perform this operation
- **404**: Not Found - The requested resource or endpoint does not
exist
- **422**: Validation Error - Request parameters failed validation
- **429**: Rate Limit - Request frequency limit for this resource
has been exceeded
- **455**: Service Unavailable - System is under maintenance
- **500**: Server Error - An unexpected error occurred while
processing the request
- **501**: Generation Failed - Content generation task execution
failed
- **505**: Feature Disabled - The requested feature is currently
unavailable
msg:
type: string
description: Response message, error description when request fails
example: success
responses:
Error:
description: Server Error
securitySchemes:
BearerAuth:
type: http
scheme: bearer
bearerFormat: API Key
description: >-
All APIs require authentication via Bearer Token.
Get API Key:
1. Visit the [API Key Management Page](https://kie.ai/api-key) to get
your API Key
Usage:
Add to request headers:
Authorization: Bearer YOUR_API_KEY
Notes:
- Keep your API Key secure and do not share it with others
- If you suspect your API Key has been compromised, reset it immediately
on the management page
````